The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 28, 2002
Filed:
Oct. 10, 2000
Richard J. Duffy, Shelby Township, MI (US);
Eugene D. Sessa, Harrison Township, MI (US);
Nylok Fastener Corp., MaComb, MI (US);
Abstract
The present invention is directed to a process for the application of fluoropolymer to a preselected area of a threaded fastener, and particularly to substantially all of the threads of the fastener. The fluoropolymer is supplied to a spray nozzle in powder form and is subjected to a triboelectrostatic charging process so that individual particles discharged from the spray nozzle are electrically charged to between about 1×10 to about 3×10 coulombs per kilogram. In the preferred form of the invention, the fluoropolymer powder is triboelectrically charged, entrained in an air stream discharged from the nozzle and directed onto the preselected area of the fastener. In this manner a generally uniform powder coating is deposited onto the preselected area of the fastener while the fastener is maintained at room temperature. Thereafter, the fastener is heated to a temperature above the melting point of the fluoropolymer to thereby coalesce the deposited powder into a continuous film coating which adheres, upon cooling, to the preselected area of the fastener. In accordance with a preferred embodiment, the fastener is heated in a manner which raises the temperature of only the preselected area of the fastener to the fluoropolymer melting point. This preferred heating technique minimizes the retention of fluoropolymer inadvertently deposited on areas of the fastener other than the preselected area, and allows this undesired fluoropolymer to be easily removed, even after heating.